Sunday, September 14, 2008

When a solar-powered Zephyr unmanned aerial vehicle, made by the British firm QinetiQ, completed a flight over Arizona July 28 that lasted three and a half days, it not only made history but also gave credibility to a quest by a number of companies and agencies to develop ultralong-endurance drones for reconnaissance or communications relay.

No longer does the idea of a UAV flying at altitudes as high as 90,000 feet for five continuous years sound like science fiction. But it’s only recently that such a notion has been taken seriously.

Derek Bye, who designs airplanes for Lockheed Martin, remembers the titter that ran through the audience when the U.S. Defense Advanced Research Projects Agency held an industry day in Arlington, Va., to announce Vulture, an unmanned plane that would fly for five years carrying a half-ton of payload and drawing just 5 kilowatts of power.

But such a thing wasn’t completely out of the blue. Seven years earlier, a strange-looking, unmanned solar-powered plane called Helios set an altitude record for propeller-driven craft of 96,863 feet. The Helios flying wing eventually broke apart off Hawaii, but U.S. defense officials saw potential in the idea.

So DARPA hatched the Vulture program. In April, the agency awarded $4 million design contracts to Boeing and Lockheed Martin, and to the specialty-UAV company Aurora Flight Sciences. They will study competing Vulture designs under an initial 12-month analytical effort.

The winner or winners will advance to a second phase, in which they will attempt to keep a subscale aircraft aloft for three months. A third phase would extend that goal to a year.

A Vulture flying at 60,000 feet could produce a continuous high-resolution image of a battlefield within a 750-mile-diameter viewing footprint, which could take some of the pressure off traditional military UAV.